/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.commons.udf.builtin;

import org.apache.iotdb.commons.udf.utils.UDFDataTypeTransformer;
import org.apache.iotdb.udf.api.access.Row;
import org.apache.iotdb.udf.api.access.RowWindow;
import org.apache.iotdb.udf.api.collector.PointCollector;
import org.apache.iotdb.udf.api.customizer.config.UDTFConfigurations;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameters;
import org.apache.iotdb.udf.api.customizer.strategy.SlidingSizeWindowAccessStrategy;
import org.apache.iotdb.udf.api.exception.UDFInputSeriesDataTypeNotValidException;
import org.apache.iotdb.udf.api.type.Type;

import java.io.IOException;
import java.util.Random;

public class UDTFEqualSizeBucketRandomSample extends UDTFEqualSizeBucketSample {

    private Random random;

    @Override
    public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations) {
        random = new Random();
        configurations
                .setAccessStrategy(new SlidingSizeWindowAccessStrategy(bucketSize))
                .setOutputDataType(UDFDataTypeTransformer.transformToUDFDataType(dataType));
    }

    @Override
    public void transform(RowWindow rowWindow, PointCollector collector)
            throws IOException, UDFInputSeriesDataTypeNotValidException {
        Row row = rowWindow.getRow(random.nextInt(rowWindow.windowSize()));
        switch (dataType) {
            case INT32:
                collector.putInt(row.getTime(), row.getInt(0));
                break;
            case INT64:
                collector.putLong(row.getTime(), row.getLong(0));
                break;
            case FLOAT:
                collector.putFloat(row.getTime(), row.getFloat(0));
                break;
            case DOUBLE:
                collector.putDouble(row.getTime(), row.getDouble(0));
            default:
                // This will not happen
                throw new UDFInputSeriesDataTypeNotValidException(
                        0,
                        UDFDataTypeTransformer.transformToUDFDataType(dataType),
                        Type.INT32,
                        Type.INT64,
                        Type.FLOAT,
                        Type.DOUBLE);
        }
    }
}
